Notebook
Monday, May 2, 2005
To Get Fed, Some Birds Wing It
Nature generally frowns on scorched-earth policies. Consider the cuckoo, which slyly lays its eggs in the nests of other birds. Upon hatching, a young cuckoo kicks out the other chicks and eggs to reduce competition for food. But there is a downside to that degree of greed: less cheeping in the nest, which generally results in less ambitious provisioning by adults.
Some kinds of cuckoos make up for this setback by cheeping as frequently and as loudly as an entire nest full of chicks, triggering intensive feeding behavior by their adoptive parents. Now scientists have identified a different trick used by another kind of cuckoo.
Horsfield's hawk-cuckoos of East Asia do not cheep much, but they do flap their wings a lot when begging for food. Keita Tanaka and Keisuke Ueda of Rikkyo University in Japan wondered whether the yellowish, beak-colored patch under the hawk-cuckoo's wings might be tricking the adults into providing more food by making them think there are more beaks in the nest.
In one experiment, the researchers showed that the cuckoos are more likely to expose the color patch under their wing the longer they've gone without a meal, suggesting they are using the visual cue as a tool for getting more food. In a second experiment, the scientists painted over some of the cuckoos' patches with dark dye. They found that those birds got fed less.
At times the adults even poked food at the wing patches.
These cuckoos may use visual cues instead of auditory ones because they typically target birds that nest on the ground, where extra noise might attract predators, the researchers theorized in the April 29 issue of the journal Science.
-- Rick Weiss
Gulf Coast Dead Zone Is Early
The "dead zone" in the Gulf of Mexico -- an area that forms every year where much of the aquatic life has died -- has begun to appear much earlier than usual, indicating it may be larger than in the past, researchers have reported.
A team of scientists from Texas A&M University, Texas A&M at Galveston, Louisiana State University and NASA recently surveyed the area in the northern Gulf of Mexico where the zone has been appearing, and found the water contains lower oxygen levels than expected this time of year.
The dead zone, located where the Mississippi and Atchafalaya rivers empty into the Gulf, typically develops in late spring and early summer following the spring flood stage of the rivers, which bring large amounts of nutrients into the Gulf. The high levels of nutrients cause blooms, or sudden growths, of phytoplankton. When the creatures die and sink to the bottom, their decomposition strips oxygen from the water, creating inhospitable conditions for other marine life.
Researchers studied an area between Southwest Pass, La., and the Calcasieu ship channel in March and found unusually high levels of "hypoxia," the term for extremely low levels of oxygen.
"We saw no hypoxia in this area until June of last year," said Steve DiMarco, an associate professor of oceanography at Texas A&M, who led the team.
-- Rob Stein
Dead Virtuosos Virtually Live
Want to hear long-dead piano soloists perform their signature works -- live in concert?
Later this month, the Raleigh, N.C., firm Zenph Studios will present the Canadian pianist Glenn Gould, who died in 1982, playing Bach's "Goldberg Variations," and France's Alfred Cortot, who died in 1962, playing a Chopin prelude.
Zenph has devised software that can reproduce every note from scratchy, decades-old recordings, exactly as they were originally made -- replicating the original pedal, damper and key positions on an actual, albeit automated, piano.
"You can say, 'Well, I'll play it just like Glenn Gould,' but you can't," said Zenph President John Q. Walker. "This is about milliseconds, and your brain, through your muscular system, can't do it."
Zenph has found a way to transcribe sound waves from old recordings with computers, coding for 10 variables, including such subtleties as when the pianist picked up his fingers, and whether the key came all the way back up before it was struck again. The technology was described last week in the magazine New Scientist.
Walker said scratchiness "is irrelevant," because the Zenph software ignores it. Gould's Bach performance is from a famous monaural LP recording made in 1955. Cortot's prelude is from 78 rpm records made in 1926.
"None of this would have been possible without the piano," Walker said. The Yamaha Disklavier Pro is built with sensors and motors allowing it to reproduce whatever is played on it, and Zenph wrote the software to make it play the old recordings.
"When we heard how good it was," Walker said, "we wondered what it would take to hear Gould play again live, except for the fact that he's dead."
-- Guy Gugliotta